<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="js/jquery-1.11.3.js"></script>
</head>
<body>

 <div>
     <button id="minus">-</button>
     <span id="result">10</span>
     <button id="add">+</button>
 </div>
<script>
    $("#minus").click(function(){
        let result=$("#result").html();
        let n=parseInt(result);
        if(n>0){
            n--;
        }
        $("#result").html(n)
    })
    $("#add").click(function(){
        let result=$("#result").html();
        let n=parseInt(result);
        n++;
        $("#result").html(n)
    })
</script>

</body>
</html>